The present invention is designed for vehicle applications where electrical power may or may not be routinely disconnected at the time of vehicle shutdown. The apparatus provides an intelligent monitoring of the electrical usage of a vehicle, particularly after engine shutdown, so that ample battery energy can be preserved to restart the vehicle at a later time. The apparatus can also provide catastrophic event monitoring for the vehicle to disconnect the battery or batteries in the event of a fire or vehicular accident.
Large commercial motor vehicles, such as heavy trucks that are powered by diesel engines, may be parked for extended periods of time. If the engine is permitted to remain operating after the vehicle is parked, the alternator should be sufficient to keep the vehicle's battery charged. However, if the engine is turned off, either intentionally by the operator, or automatically by a device such as an idle shut-down timer, while a number of electrical devices and circuits remain operational on the vehicle, the battery will begin to drain through those circuits. For example, an ignition switch will typically remain in the “on” position after an idle shut-down timer has timed out and the engine is shut down. Any circuit or electrical device that is connected through the ignition switch, which electrical device may have been left “on,” will continue to draw current and deplete the battery.
The vehicle battery must be able to provide sufficient cranking power to start the vehicle engine after a shutdown. A battery of a large vehicle typically comprises multiple storage batteries arranged in a parallel circuit array to provide greater starting current. If the battery is permitted to drain to the point where it cannot deliver the large cranking power necessary for restarting the engine, the vehicle cannot be operated. Due to the fact that a large vehicle, such as a heavy truck, may be parked for an extended time, it is appropriate to guard against the possibility that its battery will be drained to the point that will not permit the engine to be started or cranked for failure to turn off all electrical devices and disconnect the battery from the vehicle's electrical circuits. This type of circumstance may also exist in medium duty trucks used for inter- and intra-city deliveries.
It is known to place a disconnect switch in the vehicle electrical circuit between the battery and the remainder of the vehicle's electrical system for use in disconnecting the battery to prevent battery current draw that, if allowed to continue for an extended time could drain the battery to the point that the engine could not be restarted or cranked without an external source of electrical power. A battery disconnect device is typically a mechanical rotary type switch or an electro-mechanical device, such as a latching relay, which is capable of carrying relatively heavy current loads, and requires no power to remain open or closed. The battery disconnect device may be activated manually or actuated in response to conditions detected on the vehicle such as an idle shutdown timer, an accident detection system (possibly coupled to the airbag deployment circuit), a battery voltage monitoring circuit, etc.
Some examples of these automated disconnect circuits are as follows. In U.S. Pat. No. 7,460,344 [Hastings, et al.] a battery disconnect circuit is described that operates in response to a manual on/off signal or to automatically sense an arc fault, overload condition, or short circuit to disconnect the batteries from the electrical load. Another example is U.S. Pat. No. 7,612,524 [Howell, et al.] that describes a series of solid state switches mounted in parallel between the battery and the electrical load of the vehicle. The switches are associated with different power sources, i.e., direct battery fed, accessory fed and ignition fed, and are controlled by a microprocessor that uses vehicle sensors, data links, etc. to automatically control the electrical power to the various loads. These systems fail to include the vehicle alternator, starter motor and key switch from the battery as part of the control process. Their purpose is to monitor, control and protect the vehicle electrical loads. The earlier devices protected the electrical wiring and loads but failed to disconnect the battery from the alternator and starter circuits.
In some instances, solid-state devices have replaced the analog control circuitry of electro-mechanical relays. But solid-state devices have not fully replaced the electro-mechanical devices in the automotive industry and electro-mechanical devices continue to enjoy significant usage in that industry. However, none of the earlier known devices can provide precise, sensor driven control over the battery disconnect switch with the increasing use of on-board computing devices programmed to control the overall functioning of the vehicle, its engine and associated electro-mechanical and electrical subsystems.
It is one object of the present invention to monitor the electrical system of a heavy vehicle to recognize “key switch” closure while the battery is disconnected from the electrical loads. It is another object of the invention to automatically connect the battery when “key switch” closure is detected. It is also an object of the invention to continually monitor the status of the vehicle electrical system, i.e., charge, discharge, engine running, fault conditions, etc., and take appropriate actions based upon the sensed conditions. It is yet another object to electronically log and provide to the operator of the vehicle electrical system health information, e.g., charging and start system condition, wiring deterioration, as well as diagnostics and prognostics information. It is yet another object to disconnect the battery, protecting the electrical system for certain conditions; e.g. low voltage disconnect, over charge protection, short circuit protection, delayed battery disconnect after engine shutdown.
It is an additional object of the present invention to monitor onboard data from other vehicle monitoring systems to assist in fire prevention and accident detection. In monitoring the vehicle sensors the present invention responds to rollover detection or severe accident occurrence by automatically disconnecting the battery. It is a still further object of the invention to provide a manual override master switch that disables the present invention monitoring and opens the battery contactor disabling the entire vehicle electrical system. It is yet another object of the invention to provide an alarm, audible, visual, or both, to the vehicle operator immediately prior to battery disconnect either in response to a detected emergency, a sensed fault, or in response to a normal shutdown. Finally, it is an object of the present invention to provide a programmable time delay to allow for the transfer of data from on-board data compilers and storage devices to download their information prior to battery disconnect.
Other objects will appear hereinafter.